In continuous ink jet printer systems ink is supplied under pressure to the orifice cavity of a resonator body and ejects as continuous streams from an orifice plate aimed toward a print zone. The resonator body is vibrated to cause the ink streams to break up into uniformly sized and shaped droplets. A charge plate subsystem is located proximate the stream break-up point and droplets are selectively charged if intended to be non-printing ones. The charged, non-printing drops are deflected to a catcher subassembly which routes them back to the main ink supply. Uncharged drops pass on to the print zone.
U.S. Pat. No. 4,623,897 discloses an embodiment of continuous ink jet printer wherein the above-noted components are constructed as a traversing print head assembly, e.g. for printing successive lines of information with 64 orifices and related charge plate elements. This print head assembly also incorporates an air guide member located adjacent the catcher for cooperating to prevent dust from reaching the charge plate/orifice plate region.
Replacement of the print head assembly is required periodically and that, heretofore, necessitated a relatively complex, messy and time consuming job, which was not at all suitable for a customer/user. For example, the resonator and charge plate electrical connections required unplug/re-plug operations, the mechanical attachments required removal and reattachment and three ink conduits required disconnection and reconnection. The realignment of the print head was a critical and tedious task, but even more distasteful was the inevitable ink leakage that occurred during the uncoupling of the fluid supply and return lines to the orifice cavity.
U.S. Pats. Nos. 4,500,895 and 3,787,880 are exemplary of other kinds of ink jet printer devices which have aimed toward simplifying the print head replacement situation; however, neither of these approaches is suitable for a continuous ink jet printing system of the kind described above.